CARBONATE SYSTEM TRANSFORMATION IN THE SEVASTOPOL BAY (THE BLACK SEA)

2017 ◽  
Author(s):  
Natalia Orekhova ◽  
Natalia Orekhova ◽  
Eugene Medvedev ◽  
Eugene Medvedev ◽  
Sergey Konovalov ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Cycle ◽  
Black Sea ◽  
Total Alkalinity ◽  
The Black Sea ◽  
Natural State ◽  
Carbonate System ◽  
Oxygen Minimum Zones ◽  
Sevastopol Bay ◽  
Oxygen Minimum

A 20% increase of the carbon dioxide concentration in the atmosphere during the last century and a dramatic increase in nutrient load to marine systems due to human activity have resulted in pronounced carbon cycle transformation in coastal areas. Acidification and carbon dioxide increasing in the water column and appearance of oxygen minimum zones are reported for the worldwide coast. This makes ecological assessment of aquatic systems, including key cycles of elements, an important social and scientific task. In this study, we present information on the inorganic part of the carbon cycle and its transformation in the Sevastopol Bay (the Black Sea). This semi-enclosed coastal area has been under heavy anthropogenic pressure over the last century. Municipal and industrial sewage discharge, maritime activities, including excavation of bottom sediments, provide additional sources of nutrients and organic carbon. We present data on dynamics of the inorganic part of the carbon cycle from 1998 – 2015. Values of pH and total alkalinity were obtained analytically, whereas CO2, HCO3-, CO32- concentrations and pCO2 values were calculated. Dissolved inorganic carbon (DIC) and its partitioning into CO2, HCO3-, CO32- demonstrate the state of the carbon cycle and its evolution. Our observations reveal up to 2% increase of DIC from 1998 – 2015, but the value of pCO2 has increased by up to 20% in line with declining pH (acidification). Seasonal variations are far more pronounced and reveal extremes for areas of oxygen minimum zones. This results in negative consequences for the ecosystem, but these consequences for the Sevastopol Bay’s ecosystem remain reversible and the carbonate system can be restored to its natural state.

CARBONATE SYSTEM TRANSFORMATION IN THE SEVASTOPOL BAY (THE BLACK SEA)

2017 ◽  
Author(s):  
Natalia Orekhova ◽  
Natalia Orekhova ◽  
Eugene Medvedev ◽  
Eugene Medvedev ◽  
Sergey Konovalov ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Cycle ◽  
Black Sea ◽  
Total Alkalinity ◽  
The Black Sea ◽  
Natural State ◽  
Carbonate System ◽  
Oxygen Minimum Zones ◽  
Sevastopol Bay ◽  
Oxygen Minimum

A 20% increase of the carbon dioxide concentration in the atmosphere during the last century and a dramatic increase in nutrient load to marine systems due to human activity have resulted in pronounced carbon cycle transformation in coastal areas. Acidification and carbon dioxide increasing in the water column and appearance of oxygen minimum zones are reported for the worldwide coast. This makes ecological assessment of aquatic systems, including key cycles of elements, an important social and scientific task. In this study, we present information on the inorganic part of the carbon cycle and its transformation in the Sevastopol Bay (the Black Sea). This semi-enclosed coastal area has been under heavy anthropogenic pressure over the last century. Municipal and industrial sewage discharge, maritime activities, including excavation of bottom sediments, provide additional sources of nutrients and organic carbon. We present data on dynamics of the inorganic part of the carbon cycle from 1998 – 2015. Values of pH and total alkalinity were obtained analytically, whereas CO2, HCO3-, CO32- concentrations and pCO2 values were calculated. Dissolved inorganic carbon (DIC) and its partitioning into CO2, HCO3-, CO32- demonstrate the state of the carbon cycle and its evolution. Our observations reveal up to 2% increase of DIC from 1998 – 2015, but the value of pCO2 has increased by up to 20% in line with declining pH (acidification). Seasonal variations are far more pronounced and reveal extremes for areas of oxygen minimum zones. This results in negative consequences for the ecosystem, but these consequences for the Sevastopol Bay’s ecosystem remain reversible and the carbonate system can be restored to its natural state.

Oithona davisae: naturalization in the Black sea, inter-annual and seasonal dynamics, effect on the structure of the planktonic copepod community

2019 ◽  
Vol 59 (6) ◽  
pp. 1008-1015
Author(s):  
A. D. Gubanova ◽  
O. A. Garbazey ◽  
D. A. Altukhov ◽  
V. S. Mukhanov ◽  
E. V. Popova
Keyword(s):  
Black Sea ◽  
Coastal Waters ◽  
Native Species ◽  
Significant Decline ◽  
Acartia Tonsa ◽  
The Black Sea ◽  
Copepod Community ◽  
Oithona Davisae ◽  
Sevastopol Bay

Long-term (20032014) routine observations of zooplankton in Sevastopol Bay (the Black Sea) have allowed the naturalization of the invasive copepod Oithona davisae to be studied in the Black Sea coastal waters. Inter-annual and seasonal variability of the species and their impact on the native copepod community have been analyzed. The invasion of O. davisae and their undoubted dominance in terms of abundance were shown to alter the community structure but, at the same time, the abundances of the native species did not decrease, excepting the Black Sea earlier invader Acartia tonsa. A significant decline in A. tonsa numbers over the stages of O. davisae establishment and naturalization provided evidence of competition between the species. O. davisae have been demonstrated to gain competitive advantage over A. tonsa, that ensured their fast dispersal in the Black Sea, acclimatization in the new habitat and the successful competition over native species.

Long-term Changes in Sevastopol Bay (the Black Sea) with Particular Reference to the Ichthyoplankton and Zooplankton

2001 ◽  
Vol 52 (1) ◽  
pp. 1-13 ◽  
Author(s):  
A.D. Gordina ◽  
E.V. Pavlova ◽  
E.I. Ovsyany ◽  
J.G. Wilson ◽  
R.B. Kemp ◽  
...  
Keyword(s):  
Black Sea ◽  
The Black Sea ◽  
Sevastopol Bay ◽  
Long Term Changes

scholarly journals Heterotrophic denitrification vs. autotrophic anammox – quantifying collateral effects on the oceanic carbon cycle

2010 ◽  
Vol 7 (2) ◽  
pp. 1813-1837
Author(s):  
W. Koeve ◽  
P. Kähler
Keyword(s):  
Carbon Cycle ◽  
Open Ocean ◽  
The Black Sea ◽  
Fixed Nitrogen ◽  
Oxygen Minimum Zones ◽  
Collateral Effects ◽  
Nitrogen Conversion ◽  
Diffusive Fluxes ◽  
Oceanic Carbon ◽  
Heterotrophic Denitrification

Abstract. The conversion of fixed nitrogen to N2 in suboxic waters is estimated to contribute roughly a third to total oceanic losses of fixed nitrogen and is hence understood to be of major importance to global oceanic production and, therefore, to the role of the ocean as a sink of atmospheric CO2. At present heterotrophic denitrification and autotrophic anammox are considered the dominant sinks of fixed nitrogen. Recently, it has been suggested that the trophic nature of pelagic N2-production may have additional, "collateral" effects on the carbon cycle, where heterotrophic denitrification provides a shallow source of CO2 and autotrophic anammox a shallow sink. Here, we analyse the stoichiometries of nitrogen and associated carbon conversions in marine oxygen minimum zones (OMZ) focusing on heterotrophic denitrification, autotrophic anammox, and dissimilatory nitrate reduction to nitrite and ammonium in order to test this hypothesis quantitatively. For open ocean OMZs the combined effects of these processes turn out to be clearly heterotrophic, even with high shares of the autotrophic anammox reaction in total N2-production and including various combinations of dissimilatory processes which provide the substrates to anammox. In such systems, the degree of heterotrophy (ΔCO2:ΔN2), varying between 1.7 and 6, is a function of the efficiency of nitrogen conversion. On the contrary, in systems like the Black Sea, where suboxic N-conversions are supported by diffusive fluxes of NH4+ originating from neighbouring waters with sulphate reduction, much lower values of ΔCO2:ΔN2 can be found. However, accounting for concomitant diffusive fluxes of CO2, ratios approach higher values similar to those computed for open ocean OMZs. Based on our analysis, we question the significance of collateral effects concerning the trophic nature of suboxic N-conversions on the marine carbon cycle.

scholarly journals FUNCTIONAL STATE OF THE MARINE MICROALGAE CULTURES AS AN INDICATOR OF THE WATER POLLUTION LEVEL OF THE SEVASTOPOL BAY

2021 ◽  
pp. 83-90
Author(s):  
L.V. Stelmakh ◽  
◽  
I.M. Mansurova ◽  
Keyword(s):  
Functional State ◽  
Black Sea ◽  
Phaeodactylum Tricornutum ◽  
Inhibitory Effect ◽  
The Black Sea ◽  
Pollution Level ◽  
Sevastopol Bay ◽  
Algae Growth ◽  
Taxonomic Affiliation

The possibility of using cultures of Black Sea planktonic microalgae of different taxonomic affiliation to assess the quality of the aquatic environment based on the assessment of their functional state is shown. The research was carried out on the diatom Phaeodactylum tricornutum, three dinoflagellates species Prorocentrum cordatum, Prorocentrum pusillum and Gyrodinium fissum, as well as the coccolithopho-ride Emiliania huxleyi. It was found that the waters of the Sevastopol Bay in the period from May to August 2021 in 50% of cases had a weak inhibitory effect on the growth of the tested species. In other cases, algae growth was either stimulated or the effect of pollution on cultures was not revealed. The need for using several types of algae in carrying out complex work on water biotesting of the coastal are-as of the Black Sea is highlighted.

scholarly journals Peculiarities of Macro- and Microelement Accumulation in Bottom Sediments of the Crimean Coastal Water Areas (the Black Sea) with Different Water Exchange Intensity based on XRF Data

2021 ◽  
Author(s):  
E. A. Kotelyanets ◽  
Keyword(s):  
Black Sea ◽  
Bottom Sediments ◽  
Water Exchange ◽  
Fluorescence Analysis ◽  
The Black Sea ◽  
Geochemical Background ◽  
Local Pollution ◽  
Kerch Strait ◽  
Sevastopol Bay ◽  
High Concentrations

The paper analyzes content and spatial distribution peculiarities of macro- and microelements in the bottom sediments of Sevastopol bays, Feodosiya Gulf and Kerch Strait. Bottom sediment sampling was performed from 2005 to 2008 as well as in 2015, 2016, and 2018. Concentrations of macro- (Ti, Fe, Mn) and microelements (As, Pb, Zn, Cu, Ni, Co, Cr, V, Sr) were studied by X-ray fluorescence analysis using Spectroscan MAKS-G spectrometer. The maximal content of Cr, Co, Ni, Zn, Pb, Sr exceeding the geochemical background was found in the water areas with difficult water exchange, which include bays of the Sevastopol region under intense anthropogenic influence: the Yuzhnaya Bay, Gollandiya Bay and Kilen-Bay. In the Kazachya Bay, the least polluted in the Sevastopol bay system, the content of Cr, Co, Ni, Zn, Pb, As, Sr also exceeded their geochemical background. As illustrated by the Balaklava Bay, the paper shows the influence of local pollution sources (the Balaklavka River runoff and municipal waste water) on the microelement distribution. Sevastopol bays are characterized by high concentrations of the studied elements in the bottom sediments. In the water areas with active water exchange, i. e. Feodosiya Gulf and Kerch Strait, concentration of the studied elements, except for Ni, Zn and Cr, did not exceed on the average the geochemical background of the open Black Sea shelf areas.

scholarly journals Heterotrophic denitrification vs. autotrophic anammox – quantifying collateral effects on the oceanic carbon cycle

2010 ◽  
Vol 7 (8) ◽  
pp. 2327-2337 ◽  
Author(s):  
W. Koeve ◽  
P. Kähler
Keyword(s):  
Carbon Cycle ◽  
Open Ocean ◽  
The Black Sea ◽  
Fixed Nitrogen ◽  
Oxygen Minimum Zones ◽  
Collateral Effects ◽  
Nitrogen Conversion ◽  
Diffusive Fluxes ◽  
Oceanic Carbon ◽  
Heterotrophic Denitrification

Abstract. The conversion of fixed nitrogen to N2 in suboxic waters is estimated to contribute roughly a third to total oceanic losses of fixed nitrogen and is hence understood to be of major importance to global oceanic production and, therefore, to the role of the ocean as a sink of atmospheric CO2. At present heterotrophic denitrification and autotrophic anammox are considered the dominant sinks of fixed nitrogen. Recently, it has been suggested that the trophic nature of pelagic N2-production may have additional, "collateral" effects on the carbon cycle, where heterotrophic denitrification provides a shallow source of CO2 and autotrophic anammox a shallow sink. Here, we analyse the stoichiometries of nitrogen and associated carbon conversions in marine oxygen minimum zones (OMZ) focusing on heterotrophic denitrification, autotrophic anammox, and dissimilatory nitrate reduction to nitrite and ammonium in order to test this hypothesis quantitatively. For open ocean OMZs the combined effects of these processes turn out to be clearly heterotrophic, even with high shares of the autotrophic anammox reaction in total N2-production and including various combinations of dissimilatory processes which provide the substrates to anammox. In such systems, the degree of heterotrophy (ΔCO2:ΔN2), varying between 1.7 and 6.5, is a function of the efficiency of nitrogen conversion. On the contrary, in systems like the Black Sea, where suboxic N-conversions are supported by diffusive fluxes of NH4+ originating from neighbouring waters with sulphate reduction, much lower values of ΔCO2:ΔN2 can be found. However, accounting for concomitant diffusive fluxes of CO2, the ratio approaches higher values similar to those computed for open ocean OMZs. Based on this analysis, we question the significance of collateral effects concerning the trophic nature of suboxic N-conversions on the marine carbon cycle.

The new data on seasonal dynamics of species composition, abundance and biomass of Mollusca in the corner part of the Sevastopol bay (the Black Sea)

2018 ◽  
Vol 28 (4) ◽  
pp. 157-162
Author(s):  
M. V. Makarov
Keyword(s):  
Species Composition ◽  
Black Sea ◽  
Seasonal Dynamics ◽  
Trophic Structure ◽  
The Black Sea ◽  
Trophic Groups ◽  
Soft Sediments ◽  
Sevastopol Bay

The new data on seasonal dynamics of species composition, abundance and biomass of molluscs on soft sediments in the corner part of the Sevastopol bay were analyzed. 24 species of molluscs were recorded in 2006-2007. The microdistribution of Mollusca at stations depends on salinity. The trophic structure of molluscs’community was determinated and includes 6 trophic groups.

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